Sheet-feeding mechanism



VV. A. WEIGHTMAN AND C. H. NITSCH.

SHEET FEEDIW; WCHANISM. AWLICAUON FILED OCT, 3|

W. A. WEGHTMAN AND C. H. NITSCH.'

SHEET FEEDING MECHANISNI.

APPLICAUON `FILED OCTn 31,1919..

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sheet tends to UNITED STATES PATENT OFFICE.

VANIA, ASSIGNOIRS TO STOKES AND SMITH COMPANY, or SUMMERDALE, PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA.

SHEET-FEEDING MECHANISM.

Specification of Letters Patent.

Patented Aug. 23, 1921.

Application led October 31, 1919. Serial No. 334,646.

To @ZZ whom 'it may concern Be it lmown that We,WiLLiAM A. WEIGHT- MAN and CHAimEs H. Nirsori, citizens of the United States, and residents of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Sheet- Feeding Mechanism, of which` the following is a specification.

Our invention relates to sheet feeding mechanism, and particularly to means for feeding successive sheets from a pile.

The efficiency of automatic machines operating on successive sheets depends very largely upon the absolute regularity of the apparatus Which feeds the sheets to such machines, it sometimes being necessary not only that the sheet be fed at exactly the proper moment, but that it be positioned with perfect accuracy. This is especially true of printing presses, Where failure. to register a sheet properly means the spoiling of that sheet.

When the sheets are relatively thin and are supplied in pack form, ithis difficult to provide feeding means meeting these requirements, as pressure on the edges of the mar it and gripping mechanism is liable to tear it, especially when the sheets are fed from the bottom of the pack.

Feeding apparatus has heretofore been devised which employs suction to separate one end of the bottom sheet from the remaining sheets and introduce it to sheetengaging means, operative to withdraw the sheet from the pack and feed it to a machine for operating thereon. Our invention is of this type; but heretofore machines` of this kind have employed a reciprocating sup ort for the pack, making it necessary to shi t the Whole pack longitudinally every time a blank is fed therefrom.` This operation requires the vuse of considerable power and necessitates numerous connections, bearings, and guides for the moving parts, besides rendering the replenishing of the pack more difficult than if it were stationary.

An object-of our invention is to provide an apparatus employing suction for separating a sheet from the pack, and adapted to operate on the bottom sheet Without shifting the pack at all. Ve have also provided a reciprocating feed unit which is adapted to operate upon very light material, as Well as upon heavy stock, the moving parts. b eing relatively compact and light, permitting very rapid operation with a minimum expenditure of power, also eliminating the construction necessary to accommodate a constantly shifting support for the pile.

Where light material is used, as Well as yvhere `accurate registration of the fed sheet is desired, feeding mechanism which engages the blank by friction is unsuitable, as it tends to buckle, crease, or tear the sheet, and is likely to slip slightly, preventing proper registration. We have avoided this difficulty by providing means which first separates one end of a bottom blank from the remainder of a stationary pack, preferably Without sliding the sheet at all, and then positively engages the separated end by feeding mechanism, thus insuring both accuracy in the time of engagement and the exact point of the sheet which is engaged, as well as avoiding any tendency to tear or buckle the sheet, since frictional engagement is not utilized in withdrawing the sheet from the pack.

In the specific embodiment of our invention, we have provided a sheet-separating mechanism slidably mounted beneath the bottom of the pack adjacent one end, and the construction has been so arranged that this end of the pack is completely supported thereby throughout practically its entire extent at all times, thus preventing sagging and buckling.

Furthermore, While suction means is provided for initially separating the bottom sheet from the pack, We have disclosed means for continuing said separation independent of the action of the suction means, this construction being particularly useful Where relatively stiff sheets are used, as a very strong suction would be needed to do more than slightly separate the bottom sheet of stiff stock from the pack. 7e have disclosed means for guiding the separated end into engaging position after the release of the suction to permit the immediate operation of the feeding means Without overcoming any suction effect.

To insure accuracy in the timing of the feed, We have provided means for regulating the engagement of the feeding mechanism with the sheet by the position of the reciprocating sheet-separating mechanism, thus rendering the position of the sheet entirely certain at the time it is engaged and fed forward. In the preferred embodiment, this object is accomplished by mounting on the sheet-separating mechanism a fixed element, which operates to force the end of the sheet into engagement with the feeding mechanism, which may comprise a constantly rotating roller, only when the separating mechanism has reached the limit of its sheetseparating stroke, an arrangement which is particularly simple and effective inproduclng accurate timing and registration.

Our invention is furthermore particularly adapted to feed successive sheets from the bottom of the pack. Where accurate registration and regularity of feed are required, the problems involved in feeding the sheets from the bottom of the pack are substantially different from those connected with a top feed; and devices adapted to feed from the 'top of the pack are ordinarily utterly unfrom the bottom wheresuited for feeding the'weight of the pack rests on the bottom sheet and the supports interfere with proper withdrawal. f It is highly desirable, however,

to feed from the bottom of the pack under ordinary conditions, as such a construction permits the replenishing of the pack without interfering with the continuous operation of the feed; and while' our invention may be readily employed for feeding from the to of the pack, it is adapted to meet the added re uirements of bottom feeding.

ther objects and advantages of our constructlon will be apparent from the following description, taken in connection with the accompanying drawings, in which- Figure 1 is a top plan View of one end of the feed table, parts being broken away.

Fig. 2 is a central vertical section through Fig. l, the suction mechanism being shown in section, and

Fig. 3 1s a fragmentary end view of the reciprocating sheet engaging mechanism, the frame of the machine being broken away.

A suitable fixed support` for the pack of blanks is provided, such as'the usualA feed table 10, which is preferably provided with suitable-pack guide walls, such as rear wall 11 longitudinally adjustable in slot l2, and side walls 13 transversely adjustable in slot 14 to accommodate blanks varying in size. Guide members 15 for the front'of the pack are preferably provided, and may be transversely adjustable, as by mounting them on a rod 16 mounted at its ends on the frame of the machine. Feed table 10 is cut awa across its front end, leaving'a space beneath the forward end of the pile, in which is mounted the reci rocating feed mechanism. The latter is pre erably supported by a pair y .disclosed including a pinion 33,

of carriages 17 mounted to reciprocate in a plane parallel with the surface of feed table 10 in ways mounted on the frame of the machine. Any desired form of ways may be used, such as a block 18 mounted on the frame having a flat, track'19, along which a latterly projecting flange 20 of the carriage slides said flange being held in position, as by detachable gibs 21 engaging the upper part of said flange 20.

Any suitable means for reciprocating said carriages and the feed mechanism mounted thereon may be provided, as by connecting each carriage by link 22 with the u per end of rock arm 23 mounted on rock sha t 24,said

shaft 24 being rocked in any desired way,

as b providing an arm 25 mounted on said shaft', andecarrying a cam roller 26 engaging a track in disk cam 27, continuously rotated by gear connection with drive shaft 28. Arm 25 is preferably adjustable about shaft 24 to position the reciprocating feeding means with complete accuracy, the adjusting means disclosed consisting of adjusting screws 29 carried by arm 25 and engaging opposite sides of one rock arm 23.

uction means is provided, .operative to engage the forward end of the bottom sheet when carriages 17 are at the limit of their forward movement and to draw said bottom sheet downwardly during the return movement of the carriages, so as to cause its separated end to project into position where it is engaged at a predetermlned moment and p at a uniform .point by suitable feeding means, which operates to withdraw the bottom sheet `from beneath the pack, and feeds it forward in perfect register.

"While it will be apparent that various forms of suction elements may be provided adapted to engage the sheet during the forward movement ofthe carriages and withdraw it during the return-movement, we prefer to provide a suction roll 3 0 rotatably mounted at its en'ds in carriages 17, andprovided with a longitudinal 'suction duct 31 connecting with a plurality of longitudinally alined suction openings 32 on the face of the oll.

Means isv rovided 'for rotatin the roll lduring the orward movement o carriages 17 so as to bring suction openings 32 into contact with the front end of the bottom sheet when the carriage has reached .the limit of 1ts forward motlon, and to rotate the roller in reverse direction during the return of the carriages, to draw the end of said sheet downwardly about the roll, separating 1t from the pack. lVarious means for suitably rotating roll 30 may be used, the form 0 shown best 1n 3, mounted on the end of the roll outsi v e of its bearing in .carriage 17, and engaglng a rack 34 mounted in fxed position on the frame. While the rack and pimon have been shown as located at one end of roll 30 only, it is obvious that this construction may be used at both ends, if desired.

Furthermore, it is preferable to have the peripheral speed of roll 30 equal to the longitudinal speed of carriages 17 so that said roll 30 will have a rolling contact with the bottom of the pack, and will merely turn the forward end of the bottom sheet downwardly about the roll, without sliding it longitudinally beneath the pack; though under certain circumstances it may be desirable to vary this arrangement,

We have provided a construction b which the suction is released after the en of the bottom sheet has been separated from the pack and during the return motion of the carriage, guide means being provided for continuing the separation of said sheet end, and directing the end into position where it may be engaged by suitable feeding mechanism. For this purpose, we may use aseparator wedge 35, connected to carriages 17 as by mounting said wedge on supporting rod 36 connected at its ends to said carriages in such a way that it cannot rotate. The upper surface of separator wedge 35 is preferably flush with the surface of feed table 10, and acts as a support for the front end of the pack, exce t when the carriages are at their extreme orward position, when the front edge of the wedge is just clear of the end of the pack, permitting the suction roll 30 to pull the front of the bottom sheet lielow the point of the wedge when the carriages start their return movement, the front edge of said separator wedge being preferabiy Sughuy beveled, as a e7, to facilitate its entry between the bottom blank and pack, and to revent the feeding of more than one blank. After the suction in roll 30 is released, wedge 35 continues the separation of the bottom sheet from the pack, tho lower face 38 of said wedge acting as a ide for said sheet.

hile we have described and shown a sinle relatively narrow Separator wedge ad- ]acent the center of the pack, it is ap arent that a plurality may be utilized, and t at its width may be substantially varied.

While any desired means for transmitting suction to roll 30, and for cutting off the same at the proper moment may be employed, we have illustrated a simple construction for this purpose, including a suction cylinder 39 pivotally mounted at one end on the frame of the machine and having a reciprocating piston 40 which may be operated by a rock arm 41 having a cam roller 42 engaging a suitable slot in disk cam 27. Cylinder 39 is connected, as by tube 43, to suction duct 31 in roll 30, as by providing an inlet pipe 44, through a carriage 17 connecting with said duct and with said tube 48. By4 proper manipulation of piston 40 through cam 27 ,'-it will be evident that the suction may be applied and released at the proper moments.

We may also provide means for supporting the front end of thepack at the rear of roll 30 when the latter is in advanced position. Said means may include a plurality of supports 45 mounted on a transverse bar 46 connected at its ends to carriages 17 said supports preferably being located at or slightly below the surface of feed table 10, which may be provided with a suitably contoured extension to accommodate said supports. It will be apparent that with this vconstruction the front end of the pack will he positively supported at all times, except for the very narrow spaces between supports 45, separator wedge 35, and the roll 30.

Any suitable means for en'aging the projecting end of the bottom s eet and feeding itforward may be employed. We prefer to .provide a pair of rollers 47 and 48 for this purpose, so located that the front end of the separated sheet will project be tween said rollers, means being provided for bringing the rollers together at a redetermined time, so as to engage said seet and feed it forward. We have disclosed one construction for this purpose in which roller 47 is constantly and positively rotated, as by suitable gear connections withdrive shaft 28. Roller 48 is an idler journaled at opposite ends in bearings in carriages 17, and reciprocating with the feed mechanism. Roller 48 is so mounted and proportioned that it will press the end of the separated sheet against roller 47 at the'end of the return motion of said carriages, remaining in this position, of cam 27, long enough to feed the sheet completely to the operating mechanism. for illustrative purposes, we have shown a pair of gluing rolls 49 and means for guiding the sheet against one of said rolls; but our invention is obviously applicable to any type of machine operating upon successively fed blanks.

If desired, means may be provided for pressing the front end of the pack downward against the fedin mechanism, which is desirable, especially w en the pack is relatively'low and consequently there is slight pressure on the forward end of the bottom sheet. One form of pressing means is disclosed, including a presser bar 50 adapted to reston the top of the pack approximately above the point at which the bottom sheet is engaged by suction openings 32.

Suitable means for slidably mounting presser bar 5() to maintain it in constant engagement with the top of the pack is provided, which may consist of a slide bar 51 connected to said presser bar and slidably through proper proportioningl mounted, as in a bracket 52, carried by rod 16.

Means may be provided for retaining the presser bar in elevated position to permit the insertion of sheets on the top of the pack, as by providing a notch 53 in the slide bar engaged by spring catch 54. Said catch may also be contoured, as shown in Fig. 2, to exert an additional downward pressure on the slide bar when the pack is nearly eX- hausted and the weight of the pack at the forward end is nearly negligible.

While we have disclosed an arrangement for feeding successive sheets from the bottom of a pack, it will be apparent that this construction may readily be reversed to feed the sheets from the top of a suitably supported pack if desired; and our invention includes such a construction.

It will'be evident that we have provided a feeding mechanism which is adapted to operate with equal facility on sheets of greatly varying sizes and varying substantially in stiffness, as it is not necessary for suction roll 30 to wrap the sheet about any substantial proportion of its surface, since the depression of the outer edge of the sheet will permit separator wedge 35 to enter between said edge and the pack, it being immaterial thereafter whether the sheet is held by the suction apertures 32 or not. The construction is likewise adapted to very light and relatively fragile sheets, as the pack is supported throughout substantially'its entire length at alltimes, regardless of the position of the feeding mechanism, as separator wedge 35 is adapted to prevent the sagging of the front end of the pack when roll 30 starts its return motion, and thus prevents the feeding of two sheets, a common diiiiculty with thin stock.

Furthermore, there is no tendency to buckle such stock, as no tension is placed therein until the engagement of rollers 47 and 48 with the end of the blank; and as these rollers engage said blank throughoutl its entire width, the tendency of tear is reduced to an absolute minimum.

.The mechanism provided is also very strong, simple, compact and positive, permitting it to be used in relatively small spaces in connection with machines operating upon sheets, and the entire mechanism is operated from a single driveshaft. In the specific construction disclosed, the feeding mechanism is mounted as a unit, and may be readily removed by detaching gibs 21, permitting adjust-ment, repair and replacement thereof without disturbing the operating connections of the feed.

lVhile it is desirable that means be provided for positively rotating roll 30, it will be apparent that the mechanism will be operative without such means, the frictional engagement of said roll with the bottom sheet serving to rotate it when carriages 17 are reciprocated; and our invention includes such an arrangement.

hile we have described a preferred embodiment of our invention and certain modifications thereof, it will be apparent that many other changes may be made in the specific form disclosed within the scope of our invention as disclosed in this specific'ation.

We claim:

1. In sheet feeding ap aratus, a stationary support for a pack of sheets, a reciprocating carrier, sheet engaging means movably mounted on said carrier and located beneath the pack, means for shifting said engaging means during the forward movement of said carrier to engage the end of the bottom sheet and operable during the return motion of the carrier to retract the engaging means and bend said end away from the pack, and means controlled in accordance with carrier movement and having sheet-gripping enga ment only substantially at the end oereturn-movement of the carrier for gripping said end, withdrawing the sheet from the pack, and feeding it forward.

2. In sheet feeding apparatus, a stationary support for a pack of sheets, a reciprocating carrier, sheet engaging means movably mounted on said carrier and located beneath the pack, means for shifting said engaging means during the forward movement of said carrier to engage the end of said bottom sheet and operable during the return motion of the carrier to retract the engaging means and bend said end awa-v from the pack, means controlled in accordance with carrier movement and having sheet-gripping engagement only substantially at the end of return movement of the carrier for gripping said end, withdrawing the sheet from the pack, and feedin it forward, and means for releasing said s eet engaging means prior to the operation of said gripping means.

3.1In sheet feeding apparatus, a stationary support for a pack of sheets, a reciprocating carrier, suction sheet engaging means movably mounted on said carrier and located beneath the pack, means for shifting said engaging means during the forward movement of said carrier to engage the end of said bottom sheet and operable during the return motion of the carrier to retract the engaging means and bend said end away from the pack, means controlled in accordance with carrier movement and having sheet-gripping engagement only substantially at t e end of return-movement of the carrier for gripping said end, withdrawing the sheet from the pack, and feeding it forward, and means for releasing said suction prior to the operation of said gripping means.

4. In sheet feeding apparatus, a stationary support for a pack of sheets, a roller in contact with an end sheet, supporting means upon which said roller is rotatably mounted, means for reciprocating said supporting means to maintain said roller in contact with said sheet, sheet engaging means carried by' said roller, means for rotating the roller dur-- ing the advance of the supporting means to engage the end portion of the sheet, and for rotating the roller in a reverse direction during the return of the supporting means to withdraw the end portion of the sheet from the pack, and means controlled in accordance with movement of said supporting means and having sheet gripping engagement only substantially at the end of return movement of said supporting means for engaging said end portion and withdrawing the sheet from the pack.

5. In sheet feeding apparatus, a support adapted to receive a pack of sheets with one end of the pack projecting beyond an 'end of the support, reciprocating carrying means,

' suction sheet engaging means mounted thereon and maintaining supporting contact with.

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the bottom of said projecting endof the pack, means for bringing said suction means into engagement .with the end portion of the bottom sheet during the advance of the carrying means, and for retracting said suction means and said end portion during the return motion of the carrying means, an element mounted on said carrying means adapted to project between said retracted end portion and the pack during the return of the carrying means to provide a support for the pack, supporting means mounted on said carrying means and located adjacent to the suction engaging means, adapted to support the projecting end of the pack when the carrying means is in advanced position, and means for engaging said retracted end portion and withdrawing the sheet from the pack.

6. In sheet feeding apparatus, a stationary support adapted to receive a pack of sheets with one end of the pack projecting beyond an end of the support, reciprocating means mounted beneath said projecting end, said means including means for engaging an end portion of the bottom sheet and separating it from the pack, and means for supporting said projecting end` of the pack throughout substantially the entire distance from the adjacent edge of the support to the outer edge of said pack at all times, and

means for engaging said separated end portion and withdrawing it from the pack.

7 In sheet feeding apparatus, a support adapted to receive a pack of sheets having an end projecting beyond an end of the support, reciprocating means mounted beneath and adapted to support said end of the pack, means carried thereby for engaging and bending away from the pack the end portion of the bottom sheet, means controlled in accordance with movement of said reciprocating means and acting at the end of return movement of the reciprocating means for gripping said end and withdrawing the sheet from the pack, and means for forcing said end of the pack toward the reciprocating means to insure engagement of the bottom blank.

8. In sheet feeding apparatus, a support adapted to receive a pack of sheets having an end projecting beyond an end of the support, reciprocating means mounted beneath and adapted to support said end of the pack, means carried thereby for engaging and bending away from the pack an end portion of the bottom sheet, means for gripping said end portion and withdrawing the sheet from the pack, presser means resting on the pack and slidably mounted to maintain contact with the pack, adapted to press the end -of the pack toward the reciprocating means to insure engagement of the bottom sheet, and a detent for holding said presser means out of contact with the pack to permit the insertion of additional sheets on the top of said pack.

9. In sheet feeding apparatus, a support adapted to receive a pack of sheets having an end projecting beyond an end of the support, means reciprocating beneath said end of the pack and adapted to engage the bottom sheet adjacent its projecting end and bend it away from the ack, means for gripping said end and withdrawing the sheet from the pack, and means for supporting said end of the pack between the adjacent end of the support and the engaging means during the reciprocation, of said engaging means.

10. In sheet feeding apparatus, a support fora sheet stack, a carrler having forward and return movement, means on the carrier for bending down the end of a sheet and. holding the sheet during a part of the return movement, a sheet gripping and feeding member having a stationary location in relation to the sheet stack and a complemental gripping and feeding member on the carrier and arranged to coperate with the stationary member substantially at the end of the carrier return movement to grip and feed the sheet.

11. In sheet feeding apparatus, a support for a stack of sheets, a carrier having forward and return movement in relation to the stack, a suction gripper on the carrier acting to seize a sheet near its forward end and bend the end of the sheet down during the return movement of the carrier, a feed roll mounted on a stationary axis in relation to the sheet stack and a complemental on the carrier to direct the bent sheet to- 15 feed roll on the carrier brought into opera- Ward the feed roll and another feed roll tive relation to the stationary roll substanmounted ,on a stationary axis in relation tially at the end of carrier return movement to the sheet stack and arranged to grip the to grip the sheet between the rolls and feed sheet between it and the first named roll it from the stack. substantially at the end of return movement 20 12. In sheet feeding apparatus, a support of the carrier, and means for driving the fOr a stack of sheets, a carrier having forrelatively fixed roll to feed the sheet from ward and return movement in relation to the stack.

the stack, a suction roll on the carrier adapt- Signed at Philadelphia, in the county of ed to seize the forward end of an exposed Philadelphia and State of Pennsylvania, 25

Y sheet and bend it away from the sheet stack this 29th da of October A. D. 1919.

during part of the return movement of the WI LIAM A. WEIGHTMAN. carrier, a feed roll on the carrier, a guide- CHARLES H. NITSCH. 

